Motor Control Device

ABSTRACT

A load control device may control power delivered from a power source, such as an alternating-current (AC) power source, to at least two electrical loads, such as a lighting load and a motor load. The load control device may include multiple load control circuit, such as a dimmer circuit and a motor drive circuit, for controlling the power delivered to the lighting load and the motor load, respectively. The load control device may adjust the rotational speed of the motor load in a manner so as to minimize acoustic noise generated by the load control device and reduce the amount of time required to adjust the rotational speed of the motor load. The load control device may remain powered when one of the electrical loads (e.g., the lighting load) has been removed (e.g., electrically disconnected or uninstalled) and/or has failed in an open state (has “burnt out” or “blown out”).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/552,625, filed Dec. 16, 2021; which is a continuation of U.S. patentapplication Ser. No. 17/001,143, filed Aug. 24, 2020, now U.S. Pat. No.11,205,985, issued Dec. 21, 2021; which is a continuation of U.S. patentapplication Ser. No. 16/003,864, filed on Jun. 8, 2018, now U.S. Pat.No. 10,756,662, issued Aug. 25, 2020; all of which claim priority toU.S. Provisional Patent Application No. 62/517,478, filed Jun. 9, 2017,the entire disclosures of which are incorporated by reference herein.

BACKGROUND

Ceiling fans often include a motor for rotating the fan blades as wellas a light source for illuminating the space in which the ceiling fan ismounted. In some installations, the ceiling fan may receive a singlepower feed and a single switch (e.g., a mechanical toggle switchinstalled in an electrical wallbox) may be used to control the powerdelivered from an alternating-current (AC) power source to both themotor and the light source. In other installations, the motor and thelight source may receive separate power feeds and may be controlledindependently by a wall-mounted control device. For example, awall-mounted dual load control device may comprise a motor drive circuitconnected to the motor of the ceiling fan via a first electrical wiringand a dimming circuit connected to the light source of the ceiling fanvia a second electrical wiring.

The motor drive circuit may comprise one or more capacitors that may beelectrically coupled in series with the motor to adjust the rotationalspeed of the motor to one or more rotational speeds (e.g., rotationalspeeds less than a maximum rotational speed). In some cases, thecapacitors may be electrically coupled in parallel to provide one ormore additional rotational speeds. If the capacitors are coupled inparallel when the voltages across the capacitors have differentmagnitudes, acoustic noise may be generated in the load control device(e.g., due to a large circulating current being generated in thecapacitors), which can be bothersome to a user of the load controldevice. In addition, repetitive occurrences of the large circulatingcurrent may damage the capacitors and other electrical components of theload control device.

Some wall-mounted dual load control devices include digital controlcircuits (e.g., a processing circuit, such as a microprocessor) forcontrolling the motor drive circuit and the dimming circuit (e.g., usinga phase-control dimming technique) and/or for providing advancedfeatures or feedback to a user. Such wall-mounted dual load controldevices typically each include a power supply for generating a supplyvoltage for powering the processing circuit. The power supply may becoupled in parallel with the dimming circuit and may be configured toconduct current through the light source to generate a direct-current(DC) supply voltage when a controllably conductive device of the dimmingcircuit is non-conductive each half-cycle of the AC power source. Sinceit may be undesirable to conduct current through the motor load when themotor is off, the power supply may be configured to conduct currentthrough the light source in order to generate the supply voltage. If thelight source is removed from the ceiling fan and/or has failed in anopen circuit (e.g., is “burnt out” or “blown out”), the power supplywill not be able to conduct current through the light source to generatethe supply voltage and the microprocessor will be unpowered. As aresult, the wall-mountable smart dual load control device becomeunpowered and thus will not be able to control the power delivered tothe motor when the light source is removed from the ceiling fan and/orhas failed in an open circuit.

SUMMARY

As described herein, a load control device (e.g., a dual load controldevice) may control power delivered from a power source, such as analternating-current (AC) power source, to at least two electrical loads,such as a lighting load and a motor load. The load control device maycomprise a first load control circuit (e.g., a dimmer circuit) forcontrolling the power delivered to the lighting load and a second loadcontrol circuit (e.g., a motor drive circuit) for controlling the powerdelivered to the motor load. The load control device may also comprise acontrol circuit that may control the first and second load controlcircuits to control the power delivered to the first and secondelectrical loads, respectively.

The load control device may adjust the rotational speed of the motorload in a manner so as to minimize acoustic noise generated by the loadcontrol device and reduce the amount of time required to adjust therotational speed of the motor load. The motor drive circuit may comprisefirst and second capacitors, and first and second controllable switchingcircuits coupled in series with the first and second capacitors,respectively. The control circuit may control the first controllableswitching circuit to electrically couple the first capacitor in seriesbetween the AC power source and the motor load to cause the motor loadto rotate at a first rotational speed, and to control the secondcontrollable switching circuit to electrically couple the secondcapacitor in series between the AC power source and the motor load tocause the motor load to rotate at a second rotational speed. The motordrive circuit may further comprise first and second resistors configuredto be coupled in parallel with the first and second capacitors,respectively, when the respective capacitor is electrically coupled inseries between the AC power source and the motor load.

When the control circuit receives a command to change the motor loadfrom the first rotational speed to the second rotational speed, thecontrol circuit is configured to control the first controllableswitching circuit to disconnect the first capacitor from the serieselectrical connection between the AC power source and the motor load atapproximately a first zero-crossing of the AC power source, wait for await time period to allow the first capacitor to discharge through thefirst resistor; and subsequently control the second controllableswitching circuit to connect the second capacitor in series electricalconnection between the AC power source and the motor load atapproximately a second zero-crossing of the AC power source. Inaddition, the control circuit may be configured to cause the motor loadto rotate at a third rotational speed by controlling the first andsecond controllable switching circuits to electrically couple the firstand second capacitors in parallel electrical connection, where theparallel combination of the first and second capacitors is coupled inseries electrical connection between the AC power source and the motorload. As a result of controlling the first and second switching circuitsin this manner, the magnitude of a circulating current that may beconducted through the first and second capacitors when the first andsecond controllable switching circuit are rendered conductive may bereduced, which may prevent damage to the first and second capacitors andthe first and second controllable switching devices.

In addition, the load control device may remain powered when one of theelectrical loads (e.g., the lighting load) has been removed (e.g.,electrically disconnected or uninstalled) and/or has failed in an openstate (has “burnt out” or “blown out”). The load control device maycomprise a power supply that may be coupled to conduct a chargingcurrent through the first electrical load (e.g., the lighting load) forgenerating a supply voltage. The load control device may furthercomprise a controllable switching circuit coupled to the power supplyand configured to conduct the charging current through the secondelectrical load (e.g., the motor load). In response to determining thatthe charging current is not being conducted through the first electricalload, the control circuit may be configured to render the controllableswitching circuit conductive to allow the power supply to conduct thecharging current through the second electrical load. In addition, thecontrol circuit may enter an error state and may turn off the secondelectrical load in response to determining that the charging current isnot being conducted through the first electrical load. The controlcircuit may store present states of the first and second load controlcircuits in the memory when operating in the error state, and may to thefirst and second load control circuits according to the states stored inthe memory when exiting the error state.

In addition, a method of controlling power delivered from analternating-current (AC) power source to a motor load is disclosedherein. The method may comprise: (1) controlling a first controllableswitching circuit to electrically couple a first capacitor in seriesbetween the AC power source and the motor load to cause the motor loadto rotate at a first rotational speed; (2) controlling a secondcontrollable switching circuit to electrically couple a second capacitorin series between the AC power source and the motor load to cause themotor load to rotate at a second rotational speed; and (3) changing themotor load from the first rotational speed to the second rotationalspeed by controlling the first controllable switching circuit todisconnect the first capacitor from the series electrical connectionbetween the AC power source and the motor load at approximately a firstzero-crossing of the AC power source, waiting for a wait time period toallow the first capacitor to discharge through a first resistor, andsubsequently controlling the second controllable switching circuit toconnect the second capacitor in series electrical connection between theAC power source and the motor load at approximately a secondzero-crossing of the AC power source.

Further, a method of controlling power delivered from a power source toat least two electrical loads may comprise: (1) controlling first andsecond load control circuits to control the power delivered to the firstand second electrical loads, respectively; (2) generating a supplyvoltage by conducting a charging current through the first electricalload; (3) determining that the charging current is not being conductedthrough the first electrical load; and (4) rendering a firstcontrollable switching circuit conductive to allow the charging currentto be conducted through the second electrical load in response todetermining that the charging current is not being conducted through thefirst electrical load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an example load control system for controllingthe operation of an electrical device, such as a ceiling fan.

FIG. 2 is a simplified block diagram of an example dual load controldevice.

FIG. 3 is a simplified schematic diagram of an example dual load controldevice.

FIG. 4 is a simplified flowchart of an example actuator procedure.

FIG. 5 is a simplified flowchart of an example fault mode procedure.

FIG. 6 is a simplified schematic diagram of another example dual loadcontrol device.

DETAILED DESCRIPTION

FIG. 1 is a diagram of an example load control system 100 forcontrolling the operation of an electrical device, such as a ceiling fan110. The ceiling fan 110 may receive power from a power source, such asan alternating-current (AC) power source or a direct-current (DC) powersource. The ceiling fan 110 may be installed on the ceiling of a room101 or space in a building. The ceiling fan 110 may comprise a motorload (e.g., a first electrical load), such as a fan motor 112, forrotating a plurality of blades 114 (e.g., three blades as shown in FIG.1 ) to circulate the air in the room 101. The ceiling fan 110 maycomprise a lighting load (e.g., a second electrical load), such as alight source 116, for illuminating the room 101. The ceiling fan 110 mayalso include a control device or circuit that may be housed in a baseportion 118 and may control the motor 112 (e.g., to turn on and off,adjust the rotational speed, and/or control the direction of rotation ofthe motor) and the light source 116 (e.g., to turn on and off and/oradjust the intensity of the light source).

The load control system 100 may also comprise a dual load control device120 for controlling (e.g., individually controlling) the motor 112 andthe light source 116 of the ceiling fan 110. The dual load controldevice 120 may be configured to be electrically coupled between thepower source and the ceiling fan 110. For example, the dual load controldevice 120 may be configured to receive a hot wiring 102 from a hot sideof an AC power source as shown in FIG. 1 . The dual load control device120 may comprise first and second controlled outputs (e.g., a motorcontrol output and a lighting control output) that may be coupled to theceiling fan 110 through a motor control wiring 104 and a lightingcontrol wiring 106, respectively, for individually controlling the motor112 and the light source 116 of the ceiling fan. The ceiling fan 110 mayalso be coupled to a neutral side of the AC power source through aneutral wiring 108. The dual load control device may comprise one ormore actuators for controlling the motor 112 (e.g., the on and off stateand/or the rotational speed of the motor) and the light source 116(e.g., the on and off state and/or the intensity of the light source).

The dual load control device 120 may be configured to receive wired orwireless signals, such as radio-frequency (RF) signals 109, forcontrolling the motor 112 and/or the light source 116 of the ceiling fan110. The load control system 100 may comprise a remote control device130 (e.g., a battery-powered RF remote control) for transmitting RFsignals 109 including commands for controlling the motor 112 and/or thelight source 116 of the ceiling fan 110 in response to actuations of aplurality of buttons, e.g., an increase-light-intensity button 132, adecrease-light-intensity button 134, an increase-rotational-speed button136, and a decrease-rotational-speed button 138. The control device ofthe ceiling fan 110 may be configured to turn on and/or raise theintensity of the light source 116 in response to actuations of theincrease-light-intensity button 132. The control device of the ceilingfan 110 may be configured to turn off and/or lower the intensity of thelight source 116 in response to actuations of thedecrease-light-intensity button 134. The control device of the ceilingfan 110 may be configured to turn on and/or increase the rotationalspeed of the motor 112 in response to actuations of theincrease-rotational-speed button 136. The control device of the ceilingfan 110 may be configured to turn off and/or decrease the rotationalspeed of the motor 112 in response to actuations of thedecrease-rotational-speed button 138. The remote control device 130 maycomprise additional buttons for selecting presets and/or separatelyturning on and off and/or adjusting the power delivered to the motor 112and the light source 114. One will recognize that the control device ofthe ceiling fan 110 may also and/or alternatively be configured toreceive control signals from a control device via a wired communicationlink.

The operation of the load control system 100 (e.g., the operation of theceiling fan 110) may be programmed and configured using, for example,the mobile device or other network device (e.g., when the mobile deviceis a personal computing device). The mobile device may execute agraphical user interface (GUI) configuration software for allowing auser to program how the load control system 100 will operate. Forexample, the configuration software may run as a PC application or a webinterface. Examples of configuration procedures for load control systemsare described in greater detail in commonly-assigned U.S. Pat. No.7,391,297, issued Jun. 24, 2008, entitled HANDHELD PROGRAMMER FOR ALIGHTING CONTROL SYSTEM; U.S. Patent Application Publication No.2008/0092075, published Apr. 17, 2008, entitled METHOD OF BUILDING ADATABASE OF A LIGHTING CONTROL SYSTEM; and U.S. Patent ApplicationPublication No. 2014/0265568, filed Mar. 14, 2013, entitledCOMMISSIONING LOAD CONTROL SYSTEMS, the entire disclosures of which areincorporated by reference herein.

FIG. 2 is a simplified block diagram of an example load control device200 (e.g., a dual load control device), which may be deployed as thedual load control device 120 of the load control system 100 shown inFIG. 1 . The load control device 200 may be configured to control thepower (e.g., the amount of power) delivered to first and secondelectrical loads 202, 204 (e.g., a light source and a motor,respectively, of a ceiling fan, such as the ceiling fan 110 shown inFIG. 1 ). The load control device 200 may have a hot terminal H adaptedto be coupled to an alternating-current (AC) power source 206 forreceiving an AC mains line voltage V_(AC). The load control device 200may also comprise a first controlled-hot terminal CH1 (e.g., a lightcontrol or dimmed hot terminal) adapted to be coupled to the firstelectrical load 202 and a second controlled-hot terminal CH2 adapted tobe coupled to the second electrical load 204.

The load control device 200 may comprise a first load control circuit210 (e.g., a dimmer circuit) coupled between the hot terminal H and thefirst controlled hot terminal CH1 for controlling the power delivered tothe first electrical load 202 (e.g., the light source). The load controldevice 200 may comprise a second load control circuit 212 (e.g., a motorcontrol circuit) coupled between the hot terminal H and the secondcontrolled hot terminal CH2 for controlling the power delivered to thesecond electrical load 204 (e.g., the motor). The load control device200 may also comprise a control circuit 214 coupled to the first andsecond load control circuits 210, 212, for controlling the respectiveelectrical loads. The control circuit 214 may include one or more of aprocessor (e.g., a microprocessor), a microcontroller, a programmablelogic device (PLD), a field programmable gate array (FPGA), anapplication specific integrated circuit (ASIC), or any suitablecontroller or processing device. The load control device 200 maycomprise a memory (not shown) configured to store operationalcharacteristics of the load control device (e.g., present states of thefirst and second load control circuits 210, 212, etc.). The memory maybe implemented as an external integrated circuit (IC) or as an internalcircuit of the control circuit 214.

The load control device 200 may further comprise a zero-cross detectcircuit 216 coupled in parallel with the first load control circuit 210.The zero-cross detect circuit 216 may generate a zero-cross controlsignal V_(ZC) representative of the zero-crossing points of the AC linevoltage V_(AC) of the AC power source 206 in response to a voltagedeveloped across the first load control circuit 210. The control circuit214 may receive the zero-cross control signal V_(ZC) for controlling thefirst and second load control circuits 210, 212 relative to thezero-crossings of the AC line voltage V_(AC).

The control circuit 214 may generate a first drive signal V_(DR1) (e.g.,one or more drive signals) for controlling the first load controlcircuit 210. The first load control circuit 210 may comprise acontrollably conductive device, for example, a relay and/or abidirectional semiconductor switch, such as, a triac, a field-effecttransistor (FET) in a rectifier bridge, two FETs in anti-seriesconnection, one or more insulated-gate bipolar junction transistors(IGBTs), or other suitable semiconductor switching circuit. The controlcircuit 214 may be configured to control the first load control circuit210 to turn the first electrical load 202 on and off. The controlcircuit 214 may be configured to render the controllably conductivedevice of the first load control circuit 210 conductive and/ornon-conductive at predetermined times relative to the zero-crossingpoints of the AC waveform (e.g., in response to the zero-cross controlsignal V_(ZC)) using a phase-control dimming technique (e.g., a forwardphase-control dimming technique and/or a reverse phase-control dimmingtechnique) to adjust the amount of power delivered to the firstelectrical load (e.g., to adjust the intensity of a light source).

The control circuit 214 may generate a second drive signal V_(DR2)(e.g., one or more drive signals) for controlling the second loadcontrol circuit 212. The control circuit 214 may be configured tocontrol the second load control circuit 212 to turn the secondelectrical load 204 on and off. The control circuit 214 may beconfigured to control the second load control circuit 212 to control theamount of power delivered to the second electrical load 204. Forexample, the control circuit 214 be configured to control the secondload control circuit 212 to control the rotational speed and/ordirection of the motor. The control circuit 214 may be configured tocontrol the rotational speed to one or more discrete motor speedsbetween a minimum speed and a maximum speed. In addition, the controlcircuit 214 may be configured to continuously vary the rotational speedof the motor between the minimum speed and the maximum speed. Thecontrol circuit 214 may be configured to control the second load controlcircuit 212 relative to the zero-crossings of the AC line voltageV_(AC).

The load control device 200 may further comprise one or more actuators218 for receiving user inputs. The control circuit 214 may be configuredto control the first and second load control circuits 210, 212 inresponse to actuations of the actuators 218. For example, the controlcircuit 214 may be configured to turn on and off and/or adjust anintensity of a light source controlled by the first load control circuit210 in response to actuations of the actuators 218. In addition, thecontrol circuit 214 may be configured to control the rotational speedand/or direction of a motor controlled by the second load controlcircuit 212 in response to actuations of the actuators 218. The controlcircuit 214 may wait for a timeout period T_(TIMEOUT) (e.g.,approximately 500 milliseconds) after the last command for controllingthe motor was received (e.g., after the last actuation of the actuators)to adjust the rotational speed of the motor before controlling thesecond load control circuit 212 to adjust the rotational speed of themotor.

The load control device 200 may further comprise one or more visualindicators, such as light-emitting diodes (LEDs) 220, for providingvisual feedback to a user of the load control device. For example, thecontrol circuit 214 may be configured to illuminate the LEDs 220 toprovide feedback of a present intensity of a light source controlled bythe first load control circuit 210 and/or a present rotational speed ofa motor controlled by the second load control circuit 212.

The load control device 200 may comprise a communication circuit 222.The communication circuit 222 may comprise a wireless communicationcircuit, such as, for example, a radio-frequency (RF) transceivercoupled to an antenna for transmitting and/or receiving RF signals, anRF transmitter for transmitting RF signals, an RF receiver for receivingRF signals, or an infrared (IR) transmitter and/or receiver fortransmitting and/or receiving IR signals. The communication circuit 222may also comprise a wired communication circuit configured to be coupledto a wired control link, for example, a digital communication linkand/or an analog control link, such as a 0-10V control link or apulse-width modulated (PWM) control link. The communication circuit 222of the load control device 200 may also be responsive to one or moremaintained switches and/or momentary switches. In addition, thecommunication circuit 222 may be coupled to the electrical wiringconnected to the load control device 200 for transmitting a controlsignal via the electrical wiring using, for example, a power-linecarrier (PLC) communication technique. An example of a load controlsystem having control device configured to transmit control signals viaelectrical wiring is described in greater detail in commonly-assignedU.S. Pat. No. 8,471,687, issued Jun. 25, 2013, entitled METHOD ANDAPPARATUS FOR COMMUNICATING MESSAGE SIGNALS IN A LOAD CONTROL SYSTEM,the entire disclosure of which is incorporated by reference herein.

The load control device 200 may also include a power supply 230. Thepower supply 230 may generate a direct-current (DC) supply voltageV_(CC) for powering the control circuit 214 and the other low-voltagecircuitry of the load control device 200. The power supply 230 may becoupled in parallel with the first load control circuit 210. The powersupply 230 may be configured to conduct a charging current through thefirst electrical load 202 to generate the supply voltage V_(CC) (e.g.,through a first charging path 232 as shown in FIG. 2 ). When the powersupply 222 is conducting the charging current through the firstelectrical load 202, the zero-cross detect circuit 216 will generateindications of the zero-crossings of the AC waveform in the zero-crosscontrol signal V_(ZC).

If the first electrical load 202 fails as an open circuit (e.g., thelight source is “burnt out” or “blown out”) and/or the first electricalload 202 is removed, the first charging path 232 may be interrupted andthe power supply 230 may not be able to charge through the firstelectrical load. The control circuit 214 may be configured to detect ifthe first electrical load 202 is failed or missing in response to thezero-cross detect signal V_(ZC) since the charging current cannot beconducted through the first electrical load. For example, if the controlcircuit 214 determines at the zero-crossings are not present in thezero-cross detect signal V_(ZC) for a predetermined number ofconsecutive half-cycles (e.g., four consecutive half-cycles), thecontrol circuit 214 may determine that the first electrical load 202 isfailed or missing.

The load control device 200 may further comprise a switching circuit 234coupled between the power supply 230 and the second controlled hotterminal CH2. The control circuit 214 may generate a switch controlsignal V_(SW) for rendering the switching circuit 234 conductive andnon-conductive. During normal operation (e.g., when the first electricalload 202 is present), the control circuit 214 may render the switchingcircuit 234 non-conductive to allow the power supply to conduct thecharging current through the first electrical load 202 (e.g., throughthe first charging path 232). When the control circuit 214 determinesthat the first electrical load 202 is failed or missing, the controlcircuit may be configured to close the switching circuit 234 to allowthe power supply 230 to conduct the charging current through theswitching circuit 234 and the second electrical load 204 (e.g., througha second charging path 236 as shown in FIG. 2 ). Since the secondelectrical load 204 may be a motor, the control circuit 214 may beconfigured to turn the second electrical load off when the switchingcircuit 234 is conductive and the charging current is being conductedthrough the second electrical load 204.

FIG. 3 is a simplified schematic diagram of an example load controldevice 300 (e.g., the dual load control device 120 of FIG. 1 and/or theload control device 200 of FIG. 2 ) for controlling the amount of powerdelivered to multiple electrical loads (e.g., a light source and amotor, respectively, of a ceiling fan). The load control device 300 mayhave a hot terminal H adapted to be coupled to a power source (e.g., theAC power source 206) for receiving an AC mains line voltage. The loadcontrol device 300 may also comprise a first controlled-hot terminal CH1(e.g., a light control or dimmed hot terminal) adapted to be coupled toa first electrical load (e.g., the first electrical load 202, such as alight source) and a second controlled-hot terminal CH2 adapted to becoupled to a second electrical load (e.g., the second electrical load204, such as a motor).

The load control device 300 may comprise a first load control circuit310 (e.g., a dimmer circuit) electrically coupled between the hotterminal H and the first controlled hot terminal CH1 for controlling thepower delivered to the first electrical load (e.g., the light source).The load control device 300 may comprise a second load control circuit312 (e.g., a motor control circuit) electrically coupled between the hotterminal H and the second controlled hot terminal CH2 for controllingthe power delivered to the second electrical load (e.g., the motor). Theload control device 300 may also comprise a control circuit 314 coupledto the first and second load control circuits 310, 312, for controllingthe respective electrical loads. The control circuit 314 may include oneor more of a processor (e.g., a microprocessor), a microcontroller, aprogrammable logic device (PLD), a field programmable gate array (FPGA),an application specific integrated circuit (ASIC), or any suitablecontroller or processing device. The load control device 300 may furthercomprise a zero-cross detect circuit (not shown) coupled in parallelwith the first load control circuit 310 for generating a zero-crosscontrol signal representative of the zero-crossing points of the AC linevoltage of the AC power source.

The first load control circuit 310 may comprise a controllablyconductive device, such as two field-effect transistors (FETs) Q340,Q342 that are coupled in anti-series connection between the hot terminalH and the first controlled hot terminal CH1. The junction of the FETsQ340, Q342 may be coupled to circuit common. The controllably conductivedevice of the first load control circuit 310 may further comprise, forexample, a thyristor (such as a triac), a field-effect transistor (FET)in a rectifier bridge, one or more insulated-gate bipolar junctiontransistors (IGBTs), or other suitable bidirectional semiconductorswitch. The control circuit 314 may generate a dimming control signalV_(DIM) for controlling the FETs Q340, Q342 of the first load controlcircuit 310 to conduct a first load current I_(LOAD1) through the firstelectrical load. The dimming control signal V_(DIM) may be coupled tothe gates of the FETs Q340, Q342 via respective gate resistors R344,R346. The control circuit 314 may be configured to render the FETs Q340,Q342 conductive and/or non-conductive at predetermined times relative tothe zero-crossing points of the AC waveform (e.g., in response to thezero-cross detect circuit) using a forward phase-control dimmingtechnique and/or a reverse phase-control dimming technique to adjust theamount of power delivered to the first electrical load (e.g., to adjustthe intensity of a light source). During the positive half-cycles of theAC power source, the first load current I_(LOAD1) may be conductedthrough the drain-source channel of the first FET Q340 and a body diodeof the second FET Q342. During the negative half-cycles of the AC powersource, the first load current I_(LOAD1) may be conducted through thedrain-source channel of the second FET Q342 and a body diode of thefirst FET Q340.

The control circuit 314 may generate a plurality of fan speed controlsignals V_(FS1), V_(FS2), V_(FS3) for controlling the second loadcontrol circuit 312 to control the second electrical load to a pluralityof discrete power levels (e.g., a plurality of discrete rotationalspeeds of a motor, such as a motor of a ceiling fan). The second loadcontrol circuit 312 may comprise a first switching circuit, such as afirst single-pole double-throw (SPDT) relay 350, coupled between the hotterminal H and the second controlled hot terminal CH2. The controlcircuit 314 may generate the first fan speed control signal V_(FS1) forswitching the first relay 350 between a first position X (e.g., in whicha movable contact of the relay is connected to a first stationarycontact) and a second position Y (e.g., in which the movable contact ofthe relay is connected to a second stationary contact). When the firstrelay 350 is controlled to the first position X, the AC line voltage maybe coupled across the second electrical load, such that the secondelectrical load is controlled to a full power level (e.g., the motor ofthe ceiling fan is controlled to a maximum rotational speed or fullspeed). While the first relay 350 is shown as a SPDT relay in FIG. 3 ,the first relay could be replaced by a single-pole single-throw (SPST)relay.

The second load control circuit 312 may further comprise second andthird switching circuits, such as respective SPDT relays 360, 370, thatare coupled in series with respective capacitors C362, C372 between thehot terminal H and the second controlled hot terminal CH2. The controlcircuit 314 may generate the second and third fan speed control signalsV_(FS2), V_(FS3) for switching each of the respective relays 360, 370between a first position X and a second position Y. The first and secondcapacitors C362, C372 may have different capacitances, e.g., 3.3 μF and5.6 μF, respectively. When the second relay 360 is controlled to thefirst position X, the first capacitor C362 may be coupled in serieselectrical connection between the AC power source and the secondelectrical load. When the third relay 370 is controlled to the firstposition X, the second capacitor C372 may be coupled in serieselectrical connection between the AC power source and the secondelectrical load.

When only the first capacitor C362 is coupled in series with the secondelectrical load (e.g., the second relay is in position X and the firstand third relays 350, 370 are in position Y), the second electrical loadmay be controlled to a first intermediate power level (e.g., the motorof the ceiling fan may be controlled to a first intermediate rotationalspeed). When only the second capacitor C372 is coupled in series withthe second electrical load (e.g., the third relay is in position X andthe first and second relays 350, 370 are in position Y), the secondelectrical load may be controlled to a second intermediate power level(e.g., the motor of the ceiling fan may be controlled to a secondintermediate rotational speed). When both of the first and secondcapacitors C362, C372 are coupled in series with the second electricalload (e.g., the second and third relays are in position X and the firstrelay 350 is in position Y), the second electrical load may becontrolled to a third intermediate power level (e.g., the motor of theceiling fan may be controlled to a third intermediate rotational speed).The control circuit 314 may be configured to turn off the secondelectrical load by controlling all of the relays 350, 360, 370 of thesecond load control circuit 310 to the second position Y.

The second load control circuit 310 may comprise resistors R364, R374coupled in parallel with the capacitors C362, C372, respectively, forallowing the capacitors C362, C372 to discharge when the relays 360, 370are in either the first position X or the second position Y. The secondload control circuit 310 may further comprise resistors R366, R376, thatmay be coupled in parallel with the capacitors C362, C372, respectively,when the respective relays 360, 370 are in the second position Y. Theresistors R366, R376 may have smaller resistances than the resistorsR364, R374 to allow the respective capacitors C362, C372 to discharge ata faster rate when the relays 360, 370 are in the second position Y. Theresistors R366, R376 may be coupled in parallel with the respectivecapacitors C362, C372 to discharge the capacitors when the capacitorsare not electrically coupled in series between the between the AC powersource and the second electrical load (e.g., when the relays 360, 370are in the second position Y). The second load control circuit 310 mayfurther comprise a resistor R368 coupled between the first and secondcapacitors C362, C372 for limiting the magnitude of a circulatingcurrent that may flow through the capacitor C362, C372 when both of therelays 360, 370 are controlled to the first position X.

The SPDT relays 360, 370 could each be replaced by two SPST relays. Thefirst SPST relay of each pair may be controlled by one of the second andthird fan speed control signals V_(FS2), V_(FS3) and the second SPSTrelay may be controlled by the inverse of the one of the second andthird fan speed control signals V_(FS2), V_(FS3). In addition, thecontrol circuit 314 may generate additional fan speed control signalsfor controlling the SPST relays.

The control circuit 314 may control the relays 360, 370 to attempt tocouple the first and second capacitor C362, C372 in and out of thesecond load control circuit 310 (e.g., by changing the relays betweenthe first position X and the second position Y) at approximately thezero-crossings of the AC power source. This may reduce the magnitudes ofthe currents conducted through the capacitors C362, C372 when the relaysare changed to from the first position X to the second position Y andvice versa. The control circuit 314 may be configured to determine thetiming of when to control the relays 360, 370 in response to thezero-crossings of the AC power source as determined from the zero-crossdetect circuit. For example, when turning off the second electricalload, the control circuit 314 may control all of the relays 350, 360,370 to position Y at a subsequent zero-crossing. When turning on thesecond electrical load (e.g., to one of the speeds, such as the maximumrotational speed or the first, second, or third intermediate rotationalspeeds), the control circuit 314 may control the appropriate relays forthe desired rotational speed to position X at a subsequentzero-crossing.

When changing the power level of the second electrical load from onelevel to another (e.g., to change the rotational speed of the motor fromone speed to another speed), the control circuit 314 may first controlall of the relays 350, 360, 370 to position Y at a subsequentzero-crossing. The control circuit 314 may then wait for a wait timeperiod T_(WAIT) (e.g., approximately 0.5 seconds) to allow thecapacitors C362, C374 to discharge through the resistors R366, R376(e.g., at the faster rate than the capacitors could discharge throughthe respective resistors R364, R374). After the wait time periodT_(WAIT), the control circuit 314 may control the appropriate relays forthe desired rotational speed to position X at a subsequentzero-crossing.

The load control device 300 may comprise a power supply 330 forgenerating a direct-current (DC) supply voltage V_(CC) for powering thecontrol circuit 314 and the other low-voltage circuitry of the loadcontrol device 300. The power supply 330 may be coupled in parallel withthe first load control circuit 310 to conduct a charging current throughthe first load electrical load (e.g., through a first charging path 332as shown in FIG. 3 ) to charge an energy storage capacitor C380 of thepower supply 330 when the FETs Q340, Q342 of the first load controlcircuit 310 are non-conductive each half-cycle. The energy storagecapacitor C380 may be coupled to the hot terminal H and the firstcontrolled hot terminal CH1 through a full-wave rectifier bridge thatincludes diodes D381, D382, D383, D384. The diodes D383, D384 could bethe body diodes of the FETs Q340, Q342, respectively, of the first loadcontrol circuit 310. The energy storage capacitor C380 may also becoupled in series with a resistor R386 on the DC side of the rectifierbridge and may produce a DC bus voltage V_(BUS) (e.g., approximately170V). The power supply may comprise a second stage (not shown) forgenerating the supply voltage V_(CC) from the bus voltage V_(BUS) (e.g.,a linear regulator, a switching power supply, such as a buck converter,or other suitable power supply circuit for generating a low-magnitude DCsupply voltage).

The load control device 300 may further comprise a switching circuit,such as a SPDT relay 390 coupled between the power supply 330 and thesecond controlled hot terminal CH2. The control circuit 314 may generatea switch control signal V_(SW) for switching the relay 390 between afirst position X and a second position Y. When the relay 390 iscontrolled to the first position X, the energy storage capacitor C380 ofthe power supply 380 may be configured to charge through the secondcontrolled hot terminal CH2 and the second electrical load via diodesD388, D389 of the power supply 330 (e.g., through a second charging path334 as shown in FIG. 3 ). While the relay 390 is shown as a SPDT relayin FIG. 3 , the first relay could be replaced by a SPST relay.

The control circuit 314 may be configured to determine if the firstelectrical load is failed or missing (e.g., in response to thezero-cross detect circuit coupled across the first load control circuit310) and control the relay 390 to allow the energy storage capacitorC380 of the power supply 330 to charge through the second electricalload. When the first electrical load is present, the control circuit 314may control the relay 390 to the second position Y to allow the powersupply 330 to conduct the charging current through the first electricalload. In response to determining that the first electrical load isfailed or missing, the control circuit 314 may be configured to controlthe relay 390 to the first position X to allow the energy storagecapacitor C380 power supply 330 to conduct the charging current throughthe relay 390 and the second electrical load (e.g., through the secondcharging path 334).

FIG. 4 is a simplified flowchart of an example actuator procedure 400that may be executed by a control circuit of a load control device(e.g., a control circuit of the dual load control device 120, thecontrol circuit 214 of the load control device 200, and/or the controlcircuit 314 of the load control device 300). The control circuit mayexecute the actuator procedure 400 to control a plurality of relays of aload control circuit (e.g., the relays 350, 360, 370 of the second loadcontrol circuit 312 shown in FIG. 3 ) to control an electrical load,such as a motor of a ceiling fan in response to actuations of one ormore of a plurality of actuators (e.g., the actuators 218). For example,the control circuit may execute the actuator procedure 400 in responseto detecting an actuation of one the actuators at 410. The controlcircuit may first wait for a timeout period T_(TIMEOUT) (e.g.,approximately 500 milliseconds) after the last actuation of theactuators at 412 before attempting to adjust the rotational speed of themotor.

When the timeout period T_(TIMEOUT) since the last actuation expires at412 and the last actuation indicated a command to turn the motor on at414 (e.g., to turn the motor on from off), the control circuit maycontrol the appropriate relays for the desired rotational speed (e.g.,such as a maximum rotational speed or an intermediate rotational speeds)to position X at a subsequent zero-crossing at 416, before the actuatorprocedure 400 exits. If the last actuation indicated a command to changethe rotational speed of the motor at 418 (e.g., to change the speed ofthe motor from a first non-off speed to a second non-off speed), thecontrol circuit may control all of the relays to position Y at asubsequent zero-crossing at 420. The control circuit may wait for a waittime period T_(WAIT) (e.g., approximately 0.5 seconds) at 422 and thencontrol the appropriate relays for the desired rotational speed toposition X at a subsequent zero-crossing at 424, before the actuatorprocedure 400 exits. If the last actuation indicated a command to turnoff the motor at 426 (e.g., to turn the motor off from on), the controlcircuit may control all of the relays to position Y at a subsequentzero-crossing at 428 and the actuator procedure 400 may exit.

As illustrated in FIG. 4 , the control procedure 400 may only requiretwo switching events of the relays (e.g., at 420 and 424) and a singlewait period (e.g., at 422) to change the motor from a first rotationalspeed to a second rotational speed independent of the specific values ofeach rotational speed and the relays required to change between therotational speeds. The resistance of resistors R366, R376 of the loadcontrol device 300 shown in FIG. 3 may be decreased to decrease thelength of the wait time period T_(WAIT) to decrease the time required tochange between the rotational speeds.

FIG. 5 is a simplified flowchart of an example fault mode procedure 500that may be executed by a control circuit of a dual load control device(e.g., a control circuit of the dual load control device 120, thecontrol circuit 214 of the load control device 200, and/or the controlcircuit 314 of the load control device 300). The dual load controldevice may comprise first and second load control circuits (e.g., thefirst and second load control circuits 210, 212, 310, 312) forcontrolling first and second electrical loads (e.g., a light source anda motor), respectively. The control circuit may execute the fault modeprocedure 500 to enter an error state if the control circuit detectsthat current is not flowing through one of multiple electrical loadscontrolled by the load control device. For example, the control circuitmay execute the fault mode procedure 500 periodically at 510.

The control circuit may first determine if current is flowing throughthe first electrical load at 512. For example, the control circuit maydetermine if zero-crossings were not detected for a predetermined numberof half-cycles (e.g., four consecutive half-cycles). If current is notflowing through the first electrical load at 514 and the error state isnot set yet at 516, the control circuit may enter the error state at 518and store the previous states of the first and second load controlcircuits in memory at 520. The control circuit may turn off the firstload control circuit at 522 (e.g., by rendering the FETs Q340, Q342non-conductive) and turn off the second load control circuit at 524(e.g., by controlling all of the relays 350, 360, 370 of the second loadcontrol circuit 310 to the second position Y). The control circuit mayengage an alternate charging path for an internal power supply throughthe second electrical load at 526 (e.g., by controlling the relay 390 toposition X). The control circuit may then provide visual feedback of theerror state at 528 (e.g., by illuminating one or more of the visualindicators, such as the LEDs 220), before the fault mode procedure 500exits. If the control circuit is in the error state at 516, the controlcircuit may simply continue to provide the visual feedback of the errorstate at 528 and the fault mode procedure 500 may exit.

If current is flowing through the first electrical load at 514 and thecontrol circuit is in the error state at 530 (e.g., the light source hasbeen re-installed in series with the first load control circuit and/orthe fault condition has been resolved), the control circuit may exit theerror state at 532 and disengage the alternate charging path for theinternal power supply through the second electrical load at 534 (e.g.,by controlling the relay 390 to position Y). At 536, the control circuitmay turn on the first load control circuit and control the first loadcontrol circuit according to the previous state of the first loadcontrol circuit stored in the memory (e.g., as stored at 520). At 538,the control circuit may turn on the second load control circuit andcontrol the second load control circuit according to the previous stateof the second load control circuit stored in the memory (e.g., as storedat 520), before the fault mode procedure 500 exits. If current isflowing through the first electrical load at 514 and the control circuitis not in the error state at 530, the fault mode procedure 500 maysimply exit.

FIG. 6 is a simplified schematic diagram of another example load controldevice 600 (e.g., the dual load control device 120 of FIG. 1 and/or theload control device 200 of FIG. 2 ) for controlling the amount of powerdelivered to multiple electrical loads (e.g., a light source and amotor, respectively, of a ceiling fan). The load control device 600 maybe similar to the load control device 300 shown in FIG. 3 . However, theload control device 600 of FIG. 6 has three double-pole double-throw(DPDT) relays 650, 660, 670 rather than the SPDT relays 350, 360, 370,390 of the load control device 300 shown in FIG. 3 . The first DPDTrelay 650 is illustrated by two separate SPDT switches 650A and 650Bthat are controlled between positions X and Y in response to a firstrelay control signal V_(R1). The second DPDT relay 660 is illustrated bytwo separate SPDT switches 660A and 660B that are controlled betweenpositions X and Y in response to a second relay control signal V_(R2).The third DPDT relay 670 is illustrated by two separate SPDT switches670A and 670B that are controlled between positions X and Y in responseto a third relay control signal V_(R3). The first, second, and thirdrelay control signals V_(R1), V_(R2), V_(R3) may be generated by acontrol circuit 614. The control circuit 614 may include one or more ofa processor (e.g., a microprocessor), a microcontroller, a programmablelogic device (PLD), a field programmable gate array (FPGA), anapplication specific integrated circuit (ASIC), or any suitablecontroller or processing device.

The load control device 600 may comprise a second load control circuit612 that includes the first SPDT switches 650A, 660A, 670A of each ofthe DPDT relays 650, 660, 670. The first SPDT switch 650A of the firstDPDT relay 650 may be coupled between the hot terminal H and the secondcontrolled hot terminal CH2. When the first SPDT switch 650A of thefirst DPDT relay 650 is controlled to the first position X, the AC linevoltage may be coupled across the second electrical load, such that thesecond electrical load is controlled to a full power level (e.g., themotor of the ceiling fan is controlled to a maximum rotational speed orfull speed). The first SPDT switch 660A of the second DPDT relay 660 andthe first SPDT switch 670A of the third DPDT relay 670 may be coupled inseries with the first and second capacitor C362, C372, respectively.When the first SPDT switch 660A of the second DPDT relay 660 iscontrolled to the first position X, the first capacitor C362 may becoupled in series electrical connection between the AC power source andthe second electrical load. When the first SPDT switch 670A of the thirdDPDT relay 670 is controlled to the first position X, the secondcapacitor C372 may be coupled in series electrical connection betweenthe AC power source and the second electrical load. When the first SPDTswitches 650A, 650A, 670A of all of the DPDT relays 650A, 660A, 670A arein position Y, the second electrical load may be controlled off.

The second SPDT switches 650B, 660B, 670B of each of the DPDT relays650, 660, 670 may form a switching circuit for allowing the power supply330 to conduct the charging current through the second electrical load.The second SPDT switches 650B, 660B, 670B of each of the DPDT relays650, 660, 670 may be coupled between the power supply 330 and the secondcontrolled hot terminal CH2 to provide the second charging path 334through the second electrical load (e.g., when the second SPDT switches650B, 660B, 670B are each in the second position Y). The first switch650A of the first DPDT relay 650 may also be electrically connected soas to conduct the charging current through the second electrical loadwhen in the second position Y (e.g., in parallel with the second switch650B when in the second position Y). The second switch 650B of the firstDPDT relay 650 may also be electrically connected so as to be coupledbetween the hot terminal H and the second controlled hot terminal CH2when in the first position X (e.g., in parallel with the first switch650A when in the first position X). When any of the first SPDT switches650A, 650A, 670A of each of the DPDT relays 650, 660, 670 may be in thefirst position X (e.g., the second electrical load is on), the secondSPDT switches 650B, 660B, 670B may also be in the first position X andthe power supply 330 may not be able to charge through the secondelectrical load. When the first SPDT switches 650A, 650A, 670A of all ofthe DPDT relays 650A, 660A, 670A are in the second position Y (e.g., thesecond electrical load is off), the second SPDT switches 650B, 660B,670B may also be in the second position Y and the power supply 330 maybe able to charge through the second electrical load.

What is claimed is:
 1. A load control device for controlling powerdelivered from an alternating-current (AC) power source to a firstelectrical load device and to a second electrical load device, the loadcontrol device comprising: a first load control circuit electricallyconductively coupled to the AC power source, the first load controlcircuit to deliver a continuously dimmable power level to the firstelectrical load device a second load control circuit electricallyconductively coupled to the AC power source, the second load controlcircuit to deliver one of a plurality of discrete power levels to thesecond electrical load device: a power supply circuit to provide a DCvoltage, the power supply circuit coupled in electrical parallel withthe first load control circuit; a control relay selectively positionablebetween a first position that electrically conductively couples thepower supply circuit to the first electrical load device and a secondposition that electrically isolates the power supply circuit from thefirst electrical load device and electrically conductively couples thepower supply circuit to the second electrical load device; and a controlcircuit that includes zero-cross detection circuitry, the controlcircuit electrically conductively coupled to the power supply circuitry,to the controllably conductive device in the first load control circuit,the plurality of switches in the second load control circuit, and thecontrol relay, the control circuit to: adjust the first load controlcircuit to deliver the continuously dimmable power from the AC powersource to the first electrical load device; adjust the second loadcontrol circuit to deliver the one of the plurality of discrete powerlevels to the second electrical load device; monitor the zero-crossingsof the AC power source; detect, via the zero-cross detection circuitry,an absence of a defined number of zero crossings of the AC power sourceindicative of a failure of the first electrical load device; andresponsive to detection of the absence of a defined number of zerocrossings of the AC power source indicative of the failure of the firstelectrical load device, transition the control relay from the firstposition to the second position.
 2. The load control device of claim 1wherein the first load control circuit comprises: a controllablyconductive device to deliver a phase-controlled AC power to the firstelectrical load.
 3. The load control device of claim 2, furthercomprising: a continuously variable input device communicatively coupledto the control circuit, the continuously variable input device toprovide, to the control circuit, an input signal that includesinformation indicative of a desired power level to the first electricalload device; wherein the control circuit causes the first load controlcircuit to set the trigger point of the controllably conductive devicesuch that the phase-controlled AC power delivered to the firstelectrical load device corresponds to the desired power level includedin the input signal received from the continuously variable inputdevice.
 4. The load control device of claim 2 wherein the second loadcontrol circuit comprises: a parallel circuit that includes a pluralityof capacitors; and a plurality of switches, each of the plurality ofswitches coupled in electrical series with a. respective one of theplurality of capacitors: wherein the switched capacitive parallelcircuit coupled in electrical series between the AC power source and thesecond electrical load device.
 5. The load control device of claim 4,further comprising: a plurality of discrete input devices, each of theplurality discrete input devices to provide to the control circuit asignal indicative of a desired one of the plurality of discrete powerlevels; wherein the control circuit causes the at least one of: thefirst switch or the second switch to reversibly transition between theOPEN position and the CLOSE position responsive to actuation of one ofthe plurality of discrete input devices.
 6. The load control device ofclaim 4 wherein the second load control circuit. comprises: a circuit tocause the second electrical load device to selectively rotate at one ofa plurality of discrete rotational speeds including: a first rotationalspeed, a second rotational speed, and a third rotational speed; whereinthe control circuit selectively positions each of a first switch coupledin series with a first capacitor between an OPEN position and a CLOSEDposition; and a. second switch coupled in series with a second capacitorbetween an OPEN position and a CLOSED position, such that: when thefirst switch is in the CLOSED position, and the second switch is in theOPEN position, the AC power source causes the second electrical loaddevice to rotate at the first rotational speed; when the first switch isin the OPEN position, and the second switch is in the CLOSED position,the AC power source causes the second electrical load device to rotateat the second rotational speed; and When the first switch is in theCLOSED position, and the second switch is in the CLOSED position, the ACpower source causes the second electrical load device to rotate at thethird rotational speed.
 7. The load control device of claim 6 wherein totransition between the first rotational speed, the second rotationalspeed, and the third rotational speed, the control circuit to: cause atleast one of the first switch or the second switch to transition to theOPEN position and discharge at least one of the first capacitor or thesecond capacitor, respectively, through a load resistor at a first zerocrossing of the AC power supply; and cause at least one of the firstswitch or the second switch to transition to the CLOSE position at asubsequent second zero crossing of the AC power supply.
 8. A method ofcontrolling power delivered from an alternating-current (AC) powersource to a first electrical load device and to a second electrical loaddevice, the method comprising: adjusting, by control circuitry, a firstload control circuit to deliver a continuously dimmable power level froman AC power source to a first electrical load device; adjusting, by thecontrol circuitry, a second load control circuit to deliver one of aplurality of discrete power levels to a second electrical load device;monitoring, by the control circuitry via communicatively coupledzero-cross detection circuitry, zero-crossings of the AC power source;detecting, via the zero-cross detection circuitry, an absence of adefined number of zero crossings of the AC power source indicative of afailure of the first electrical load device; and responsive to detectionof the absence of the defined number of zero crossings of the AC powersource indicative of the failure of the first electrical load device,transition the control relay from a first position to a second positionsuch that: in the first position, the control relay electricallyconductively couples a power supply circuit that provides power to thecontrol circuitry to the first electrical load device; and in the secondposition, the control relay electrically isolates the power supplycircuit from the first electrical load device and electricallyconductively couples the power supply circuit to the second electricalload device.
 9. The method of claim 8 Wherein adjusting the first loadcontrol circuit to deliver the continuously dimmable power level fromthe AC power source to the first electrical load device furthercomprises: adjusting one or more controllably conductive devicesincluded in the first load control circuit to provide a phase-controlledAC power to the first electrical load.
 10. The method of claim 9,further comprising: causing, by the control circuitry, the first loadcontrol circuit to set the trigger point of the controllably conductivedevice such that the phase-controlled AC power delivered to the firstelectrical load device corresponds to a desired power level included inan input signal received from a communicatively coupled continuouslyvariable input device.
 11. The method of clam 9 wherein adjusting thesecond load control circuit to deliver one of the plurality of discretepower levels to the second electrical load device further comprises:reversibly transitioning, by the control circuitry, each of a pluralityof switches between an OPEN position and a CLOSED position, wherein eachof the plurality of switches coupled in electrical series with arespective one of a plurality of capacitors to provide a plurality ofseries connected capacitor/switch combinations and wherein each of theplurality of series connected capacitor/switch combinations is coupledin electrical parallel with the remaining plurality of series connectedcapacitor/switch combinations,
 12. The method of claim 11, furthercomprising: causing, by the control circuitry, a at least one of: afirst switch coupled in series with a first capacitor and a secondswitch coupled in electrical series with a second capacitor, toreversibly transition between the OPEN position and the CLOSE positionresponsive to actuation of one of a plurality of discrete input devices,wherein each of the plurality discrete input devices provides to thecontrol circuit a respective signal indicative of a desired one of theplurality of discrete power levels.
 13. The method of claim 12 whereinadjusting the second load control circuit to deliver one of theplurality of discrete power levels to the second electrical load devicefurther comprises: causing, by the control circuitry, the secondelectrical load device to selectively rotate at one of a plurality ofdiscrete rotational speeds including: a first rotational speed, a secondrotational speed, and a third rotational speed; selectively positioning,by the control circuitry, each of the first switch coupled in serieswith the first capacitor between the OPEN position and the CLOSEDposition; and the second switch coupled in series with the secondcapacitor between the OPEN position and the CLOSED position, such that:when the first switch is in the CLOSED position, and the second switchis in the OPEN position, the second electrical load device rotates atthe first rotational speed; when the first switch is in the OPENposition, and the second switch is in the CLOSED position, the secondelectrical load device to rotates at the second rotational speed; andwhen the first switch is in the CLOSED position, and the second switchis in the CLOSED position, the second electrical load device to rotatesat the third rotational speed.
 14. The method of claim 13 whereinselectively positioning, by the control circuitry, each of the firstswitch coupled in series with the first capacitor between the OPENposition and the CLOSED position; and the second switch coupled inseries with the second capacitor between the OPEN position and theCLOSED position further comprises: causing, by the control circuitry, atleast one of the first switch or the second switch to transition to theOPEN position and discharge at least one of the first capacitor or thesecond capacitor, respectively, through a load resistor at a first zerocrossing of the AC power supply; and causing, by the control circuitry,at least one of the first switch or the second switch to transition tothe CLOSE position at a subsequent second zero crossing of the AC powersupply.
 15. A non-transitory, machine-readable, storage device thatincludes instructions that, when executed by a control circuit thatcontrols power delivered from an alternating-current (AC) power sourceto a first electrical load device and to a second electrical loaddevice, causes the control circuit to: adjust a first load controlcircuit to deliver a continuously dimmable power level from an AC powersource to a first electrical load device; adjust a second load controlcircuit to deliver one of a plurality of discrete power levels to asecond electrical load device; monitor, via communicatively coupledzero-cross detection circuitry, zero-crossings of the AC power source;detect, via the zero-cross detection circuitry, an absence of a definednumber of zero crossings of the AC power source indicative of a failureof the first electrical load device and responsive to detection of theabsence of the defined number of zero crossings of the AC power sourceindicative of the failure of the first electrical load device,transition the control relay from a first position to a second position,such that: in the first position, the control relay electricallyconductively couples a power supply circuit that provides power to thecontrol circuitry to the first electrical load device; and in the secondposition, the control relay electrically isolates the power supplycircuit from the first electrical load device and electricallyconductively couples the power supply circuit to the second electricalload device.
 16. The non-transitory, machine-readable, storage device ofclaim 15 wherein the instructions that cause the control circuit, toadjust the first load control circuit to deliver the continuouslydimmable power level from the AC power source to the first electricalload device further cause the control circuit to: adjust one or morecontrollably conductive devices included in the first load controlcircuit to provide a phase-controlled AC power to the first electricalload.
 17. The non-transitory, machine-readable, storage device of claim16, wherein the instructions, when executed by the control circuit,further cause the control circuit to: cause the first load controlcircuit to set the trigger point of the controllably conductive devicesuch that the phase-controlled AC power delivered to the firstelectrical load device corresponds to a desired power level included inan input signal received from a communicatively coupled continuouslyvariable input device.
 18. The non-transitory, machine-readable, storagedevice of clam 16 wherein the instructions that cause the controlcircuit to adjust the second load control circuit to deliver one of thepith of discrete power levels to the second electrical load devicefurther cause the control circuitry to: reversibly transition each of aplurality of switches between an OPEN position and a CLOSED position,wherein each of the plurality of switches coupled in electrical serieswith a respective one of a plurality of capacitors to provide aplurality of series connected capacitor/switch combinations and whereineach of the plurality of series connected capacitor/switch combinationsis coupled in electrical parallel with the remaining plurality of seriesconnected capacitor/switch combinations.
 19. The non transitory,machine-readable, storage device of claim 18 wherein the instructions,when executed by the control circuit, further cause the control circuitto: cause at least one of: a first switch coupled in series with a firstcapacitor and a second switch coupled in electrical series with a secondcapacitor, to reversibly transition between the OPEN position and theCLOSE position responsive to receipt of an input signal received fromone of a plurality of discrete input devices, wherein each of theplurality discrete input devices provides to the control circuit arespective signal indicative of a desired one of the plurality ofdiscrete power levels.
 20. The non-transitory. machine-readable, storagedevice of claim 19 wherein the instructions that cause the controlcircuit to adjust the second load control circuit to deliver one of theplurality of discrete power levels to the second electrical load devicefurther cause the control circuit to: cause the second electrical loaddevice to selectively rotate at one of a plurality of discreterotational speeds including: a first rotational speed, a secondrotational speed, and a third rotational speed; and selectively positioneach of the first switch coupled in series with the first capacitorbetween the OPEN position and the CLOSED position; and the second switchcoupled in series with the second capacitor between the OPEN positionand the CLOSED position, such that: when the first switch is in theCLOSED position, and the second switch is in the OPEN position, thesecond electrical load device rotates at the first rotational speed;when the first switch is in the OPEN position, and the second switch isin the CLOSED position, the second electrical load device to rotates atthe second rotational speed; and when the first switch is in the CLOSEDposition, and the second switch is in the CLOSED position, the secondelectrical load device to rotates at the third rotational speed.
 21. Thenon-transitory, machine-readable, storage device of claim 20 wherein theinstructions that cause the control circuit to selectively position eachof the first switch coupled in series with the first capacitor betweenthe OPEN position and the CLOSED position; and the second switch coupledin series with the second capacitor between the OPEN position and theCLOSED position further comprises: cause at least one of the firstswitch or the second switch to transition to the OPEN position anddischarge at least one of the first capacitor or the second capacitor,respectively, through a load resistor at a first zero crossing of the ACpower supply; and cause at least one of the first switch or the secondswitch to transition to the CLOSE position at a subsequent second zerocrossing of the AC power supply.